i3 4170 to i7 4790 or buy ryzen instead?

Hands down, I’d say Ryzen – AT LEAST a 1600… an OC’d 4790k would still be stronger than 1500x on down. But that also means a new motherboard and ram as well. PCPartPicker part list / Price breakdown by merchantCPU: AMD – Ryzen 5 1600 3.2GHz 6-Core Processor ($170.90 @ OutletPC) Motherboard: ASRock – AB350 Pro4 ATX AM4 Motherboard ($73.88 @ OutletPC) Memory: Patriot – Viper 4 8GB (2 x 4GB) DDR4-3000 Memory ($84.99 @ Newegg) Total: $329.77 Prices include shipping, taxes, and discounts when availableGenerated by PCPartPicker 2018-04-08 23:00 EDT-0400A second hand 4790(non k) wouldn’t really be worth it. It’s got to the be the one with the ‘k’ at the end, so you can overclock that one. Unfortunately, a 4790k doesn’t come cheap. Then get either 16gb or 8gb of ram to run in dual channel – you’re actually crippling the cpu’s performance by running on one stick of ram. But with the money you’d spend on the ‘k’ cpu and the extra ram, you could just get a Ryzen 1600 build instead. TL;DR: No less than Ryzen 1600.